1. Field of the Invention
The present invention relates to systems and methods for capturing and tracking the three-dimensional (3D) coordinate path of a moving object and, in particular, to tracking and providing visual feedback for the X,Y,Z trajectory path of a swinging object such as a golf club or of a projectile such as a baseball.
2. Description of the Related Art
Various devices are used to capture path data from moving objects. For example, devices such as electronic graphic sketch pads, digitizing tablets, electronic white boards, and copy boards are widely used to capture two dimensional (2D) X,Y coordinate path data from a moving stylus being manipulated by a human user or other stylus manipulator such as a robotic arm. For example, such devices are used for real-time capture of hand-written notes, drawings and sketches, machine tool placement, robotic arm positioning, and sensory feedback for motion training. Such captured data is typically stored in computer memory or provided to a network for mass storage, manipulation, or distribution to participants in a data conference.
Sensing devices may also be used to capture and track the 3D coordinate path of a moving object. For example, it may be desired to employ such 3D tracking devices to track the X,Y,Z trajectory or path of a swinging object such as a golf club or of a projectile such as a baseball, and to provide visual feedback of the tracked path. This may be useful to a human user of the object, for example to improve a golf swing.
Conventional 3D path tracking typically has employed devices and techniques such as magnetic field motion tracking, optical tracking, CCD cameras, and mechanical articulated arms. Some such systems have typical capture rates of 120 to 3,500 samples per second, can cost between $1,500 to $30,000, and are large and cumbersome. Existing swing trajectory tracking devices include 2D optical plane sensors, magnetic field, and mechanical swinging machines. However, the 2D systems do not provide true 3D path tracking, require close sensing proximity to the object (e.g., club or bat), and provide relatively poor visual feedback. In addition, some previous systems can be prone to outside magnetic interference, can consume relatively large amounts of power, and are too cumbersome and/or constricted by wire cables are harnesses to be easily portable.